Gas burner



July 11, 1967 w. c. MILLIGAN GAS BURNER 2 Sheets-Sheet l f Filed July 7, 1965 f f T/ I l l 1/ MYC@ United States Patent O 3,330,324 GAS BURNER William C. Milligan, 1618 San Angeio Blvd., San Antonio, Tex. 78214 Filed July 7, 1%5, Ser. No. 470,175 12 Claims. (Cl. 15S- 7) This invention relates to a new gaseous fueled heating device and, more specifically, to a gas-fired kiln, furnace, oven or similar device in which heat is provided to confined space or chamber primarily in the form of radiant energy.

In the construction of gas-fired luminous wall industrial furnaces and other devices having firing panels of substantial length, the high temperature of the firing face relative to the remainder of the structure causes the firing portion of the furnace wall to expand without a correspondingly large expansion of the remaining structure. The required frequent and repeated heating and cooling cycles result in progressive cracking and deterioration of these devices. In the conventional industrial furnace, gradual deterioration of the mortar between the iirebricks or porous fuel burning elements and the firebrick themselves occurs.

This type of furnace in which a substantial portion of its interior roof or wall area serves to provide radiant energy by combustion has been severely handicapped by the materials used, the method of supplying the proper fuel-air mixture for combustion at the interior luminous Walls, and the gradual deterioration resulting from the repeated expansion and contraction of the materials during use. Since these devices have been required to use fuel-air mixtures under considerable pressure in order to penetrate the porous firebrick, the difiiculty and danger caused by expansion and contraction deterioration and the resultant rebrick or mortar cracks have been magnified. Under these conditions even a small crack allows a substantial proportion of the high pressure fuel-air mixture to penetrate into the combustion surface. This can result in an explosion inside the device, or it may provide a flame propagation path back into the pressurized gas-air mixture chamber, resulting in an even more hazardous explosion in that chamber. Under the conventional fuel-air mixture pressures required to penetrate the porous bricks at an adequate rate, even very small cracks are dangerous and special precautions must be taken. Also, because it is necessary to operate such furnaces at high temperatures, usually 1000" to 2500o F., the cracking problem is considerably magnified. These problems have proven so diiicult that none of these porous tirebrick devices has achieved significant commercial success.

It is a general object of the invention to provide a new and improved heating device.

It is a more specific object to provide a heating device having a unique type of luminous wall and gas chamber construction which effectively eliminates one or more of the aforesaid disadvantages of the prior art.

It is a specific object to provide a luminous wall construction system which will permit extremely fast furnace heat-up time combined with an extended radiating surface for a given volume of furnace.

It is another specific object to provide a simple and inexpensive means to allow any required degree -of expansion or contraction without resulting cracks or other deteriorating effects or any hazardous conditions.

It is a further object of the invention to provide a new and improved construction for heating devices which makes it possible to use a plurality of matching elements of standardized sizes and shapes which can be combined to form a heating device of a wide variety of overall sizes and configurations.

A gaseous fuel burning device constructed in accordance with the invention has a plurality of chamber defining Walls which comprise a plurality of gas permeable ceramic firing panels having firing surfaces and gaseous fuel input surfaces. The device may further include means for mounting these panels in at least one wall of the device such that the firing lsurfaces face into the chamber of the device and are arranged in juxtaposed pairs of surfaces at an angle to one another so that each surface of each pair faces the other, thus allowing interchange of radiant heat between them. The means for mounting the panels may further comprise thermal expansion absorbing and preventing means. Additional means, including the input surfaces of the panels, are provided for defining a plenum to supply gaseous fuel under pressure to the firing surface of the panels.

The organization and manner of operation of the invention, together with further objects and advantages thereof, may -best be understood by reference to the following description taken in connection with the accompanying drawings, in the several gures of which like reference numerals identify like elements, and in which:

FIG. l is a plan view, partly in section of a furnace constructed in accordance with the present invention;

FIG. 2 is a fragmentary side view, partly in section, of one wall of the furnace shown in FIG. l as seen from Within the furnace;

FIG. 3 is a fragmentary detailed vertical View of one corner, partly in section, of the furnace shown in FIG. l;

FIG. 4 is a fragmentary detailed vertical view, partly in section, of a part of the furnace shown in FIG. l; and

FIG. 5 is a similar vertical view, partly in section, of another part of the furnace shown in FIG. 1, with parts removed.

Referring to FIG. 1, depicted there is a heating device of the industrial furnace type, generally indicated by the numeral 8. The furnace 8 has four adjacent vertical firing walls 10, 11, 12 and 13 which are arranged to define a generally square furnace chamber 9.

Each of the walls lll-14 inclusive is formed with a plurality of firing tiles or panels 14.

The firing panels 14 are supported along their vertical edges abutting each other by a number of vertical side- Walls 17 within the furnace wall lll. The side walls 17 are oriented at a right angle to the plane of the furnace wall 10 and are separated from one another by a plurality of relatively thick vertical backwalls 16. The backwalls 16 are spaced from the panels 14 to define, wit-h the sidewalls 17, a duct or plenum chamber 15 behind each panel 14.

The backwalls 16 of the plenum chambers 15 lie sideby-side in spaced relation. Part of the insulating sidewalls 17 extends adjacent to the sidewalls 16 to be partly sandwiched between the adjacent backwalls 16 but also extending away from them toward the chamber 9. The rear surface of the backwalls 16, with one vertical edge 17d of the sidewalls 17, form a planar back surface 10b of the wall 16. Planar back surfaces 11b, 12b and 13b are similarly defined with respect to walls 11, 12 and 13. At the corners of the furnace 8 along the vertical abutting edges of the furnace walls 11, 12, 13 and 14, there is provided lateral thermal expansion absorbing and compensating means generally indicated at the numeral 202 FIG. 2. depicts part of the wall surface of the wall 10 as seen from within the chamber 9 with the iioor of the chamber removed to show the construction more clearly. Each of the firing panels 14 may be of two-part construction comprising a pair of adjacent vertical rectangular aasaszi 3 ring tiles 14a and 14b each of which is supported along their line of juncture a Y-shaped support element 21 mounted vertically within chamber on the backwall 16. The tiles 14a and 14b are each supported at their other vertical edges by the sidewalls 17 and are positioned at a right angle to one another. Each tile 14a and 14b has a length dimension considerably greater than the tiles breadth dimension. The tile 14a partially faces the tile 14b and vice versa, while both face generally into the chamber 9. The vertical planes of the tiles 14a and 14b Vare preferably related to the plane of the wall 10 at an angle of The backwalls 16 are, like the panels 14, adjacent to one another with the sidewalls 17, however, extending between adjacent backwalls 16 and forming a buffer between the backwalls 16. The backwall serves to bear the major part of the loading of the furnace 8 and provides thev structural rigidity for supporting the panels 14 and the sidewalls 17. These latter elements are preferably supported to bear little or no structural loading.

FIG. 3 shows in more detail the construction of the furnace walls 10 and 11 and the lateral thermal wall expansion absorbing means 2t). As the construction of each corner of the furnace 8 is essentially the same, only that between the walls 10 and 11 will be describe-d. As the mounting of the panel 14 to the vertical edges of insulating sidewalls 17 is shown in detail in FIG. 4, it will be explained in connection with that figure. The means 20 includes a right triangular-shaped (in cross-section) vertical end block 18 which may comprise one or more elemental blocks positioned or stacked along the vertical end edge of the walls 10 and 11 adjacent an end sidewall 17. The longest vertical plane surface of the block 18 is in sliding contact with a surface 19a of a relatively thin fixed corner wall 19 which extends in the direction of furnace chamber 9 at a 45 angle to both walls 10 and 11 from a fixed restraining wall 23. The restraining wall 23 lies spaced from and parallel to the planar back `surfaces 10b and 11b of the furnace walls 10 and 11 at the corner between these walls 10 and 11. Between the restraining walls 23 and the blocks 18 are means to generate a restoring force upon the blocks 1S comprising a series of coil compression springs 22 spaced vertically along the block 18 and in compression between the blocks Y 18 and the walls 23. It is to be understood that other restoring force generating means may be used and the springs 22 are illustrative of these means. The corner wall 19 is preferably of sufficient strength as to enable the removal of either wall 10 or wall 11, as for repair, without effecting the end support of the remaining wall.

As mentioned the individual firing panels 14 may be -made of a single V-shaped ceramic or may be constructed of t-wo planar pieces 14a and 14b as depicted. In the latter case, the two tiles 14a and 14b are preferably identical for ease of assembly. They meet and abut along their vertical edges 14e at the point of the V-shaped panel 14 and are supported at this point by the Y-shaped support 21 seated within the duct 15. The supports 21 are each afiixed to individual `backwalls 16 and extend from the backwall 16 to the junction of the tiles 14a and 14b.

As may best be seen in FIG. 4, the sidewalls 17 are preferably constructed with a skin of metal 17a forming the side surfaces facing the ducts 15 and the backwalls 16. The metal sheets 17a provide both structural rigidity and a better seal about the plenum chambers 15. Between the metal surfaces 17a of each sidewall 17 is a high temperature insulating filler 17 b. The filler 17b is preferably capable of resiliently absorbing compression. The sidewalls 17 are aiiixed to the backwalls 16 in a conventional manner.

It is important that adjacent ceramic panels 14 be secured in a manner to prevent gas leakage. This is done by rmly but flexibly securing or pressing against the element 14a and 1417 and against a thin strip of hightemperature batting 24 which is applied to an L-shaped lip 17L at the outer edges of metal surfaces 17a of the sidewalls 17. The vertical edge 17e of sidewall 17 facing into furnace chamber 9 extends out past the metal sheets 17a to form a layerof insulating material between the vertical outside edge surface 14S of the tiles 14a, 14b so that as the panel sections 14 are forced together under spring tension, an evenly distributed force will be applied by surfaces 14s to the protruding edge 17e of the insulating material 17b of the sidewall 17.

The means for aiiixing tiles 14a and 14b to the sidewall 17 includes a stud 26 set with its head portion in a recess 25 of the ceramic tiles 14a and 14b and with its longitudinal portion posing through a small diameter hole 25 at the bottom of the recess, through the insulation batting '24, through a similar small diameter hole in the metal surface 17a of the sidewall 17 and into a small pocket or cup 30 formed inside wall 17. Urging means comprising a spiral compression spring 27 is attached near the base of the holding stud within the cup 30. The other end of the spring 27 bears'against the metal wall portion 30a of the cup 30 to urge the T-shaped stud and thus the ceramic panels 14 against the batting 24. This spring 27 allows for thermal expansion of the tile. Thin ceramic batting insulation should preferably be placed -above and below the head of the T-shaped holding stud 26 or to prevent excess heat loss through the tension holding mechanism and panels 17a. The various holes for the longitudinal member of stud 26 are provided with suicient vertical clearance to prevent excess stress on the ceramic panels 14 during the expansion and contraction of the panels 14.

FIG. 5 shows the Y-shaped supporting element 21 which is affixed to the supporting backwall 16 to receive the interior junction 14C of the tiles14a and 1417 of the heating panel 14. The surfaces of the arms 21a ofthe Y-shaped support 21 are covered with an insulating material 24 similar to that of the batting material 24 and ,mate directly against the V-joint of the heating panels 14a and 14b. When the panel 14 is made entirely of one piece, the support 21 may be eliminated. But, even in the case where the heating panel 14 is of one generally V-shaped piece, it is desirable to use a support such as 21 to provide added rigidity.

In overall operation the furnace functions to heat the chamber 9 through the burning of fuel upon the firing surfaces of panels 14. The panels 14 are supplied with a combustible gaseous fuel, generally a mixture of petroleum or coal gas and air or oxygen, which is contained under pressure in the ducts 15. This ammable mixture of gaseous fuel passes through the generally porous heating panels 14 whereupon it burns on the firing surfaces facing the chamber 9. The heating element should preferably be of ceramic material having combustion catalytic properties for best effect.

As taught in the co-pending application of the present invention entitled Catalytic Infrared Heating Device, Serial No. 246,761, filed December 2A, 1962, much less active catalytic material can be used for the heater clement than has heretofore been considered necessary. In fact, the principal constituent of the ceramic, catalytic unit of the invention can be composed of inexpensive materials such as clays of the kaolin, ball or talc type. These clays can be used in various combinations to obtain easy workability, plasticity, and strength without aifectingithe catalytic properties desired. Also, they may be fired at Various temperatures to obtain suitable strength properties. In order to minimize the amount of vitrilcation which would occur on tiring, it may be desirable to add stabilizers such as alumina or4 zirconia to the yclay material before firing.

The very large number of minute holes which Vmust be present in the structure can be achieved by ak number of techniques, such as the use of chemical foaming, the use of a burnout material, or the use of bloated aggregate material. As a specific example, it has been found that from 25 to 100% by weight of wood or walnut flour added to a clay formula has provided good results if the burnout material is at least 1GO mesh size Vor smaller and preferably from 200 to 300 mesh. When tired at proper temperatures, the wood or walnut flour burns out leaving correspondingly small holes throughout the ceramic structure. The larger volume of minute holes left in the ceramic structure permits very high catalytic activity rates, at low cost, in contrast to standard catalytic materials.

The rigid catalytic cera-mic tiles 14a, 1412 may have fuel-air supply mixture holes as outlined in the aforementioned patent application, or they may ybe successfully utilized without holes. In the latter case, the Same hightemperature radiation characteristics will be achieved and the furnace 8 will still operate at gas inspirator plenum or gas chamber pressures which are only slightly above atmospheric pressure. In other words, the fuel-air mixture penetration pressures required for the porous material are exceptionally low. Also, the depth of penetration of the resultant radiating surface will be the same for this type as it would be for the uniformly perforated material, namely, just slightly below the case of the ridged area; i.e. no substantial penetration of the radiant or thermal energy will proceed further back toward the gas chamber than somewhat below the base of the ridged area. This means that in most cases the actual high temperature depth of penetration on the luminous wall face will normally be less than 1A" and generally will probably be somewhat less than die, even though the radiating surface temperature of the ridges would be 2000 to 2800 F, The actual surface temperature of the rear portion of the radiating ceramic panel 14 will be generally less than 200 F. These types of elements will also not be subject to gradual crawl-back or creepage of the high temperature existing on the surfaces farther back than as previously stated, which is slightly below the base of the outer ridges, for the reasons outlined in the above mentioned co-pending patent application.

The fuel-air mixture required for the individual chambers 15 may be obtained by individual fuel-air inspirator systems or by any suitable blower pre-mixing system such as also outlined in my co-pending patent application.

Instead of individual air inspirator supply systems, the individual gas chambers 15 can be properly and adequately supplied through a sufficiently large premixing or gas inspirator design which will supply a given group or all of the gas chambers 15 involved from one central supply system.

When initially lighting up the furnace the various ceramic heating panels 14 as well as all the other elements in association with the furnace will begin to expand as their temperature rises. The various elements expand in varying proportions. In ordinary furnaces, the various expansions result in great pressures and stress on the various materials which, after a number of lightups and bankings, lead to deterioration or worse. During this heatup process, the insulation of the sidewalls 17 next to the gas chamber walls by the metal 17a serves the very important function of providing not only insulation but also sealing the unburned gaseous mixture from the iire in an effective and efficient manner. This positive wall expansion and contraction checking means when used in conjunction with the spring-loaded tension holding means 2t) provides an effective way of achieving a furnace with a wide range of possible operating temperatures. When the springloaded tension means are attached to each corner and allowed to operate independently, the assembly will be free to expand or contract since the triangular Iblocks 18 at each corner will allow expansion and contraction movement. The insulation 19in yof fixed corner wall 19 is preferably of the same nature as that of insulating material of sidewalls 17 which may be the same as the high temperature insulating batting 24 and 24 used between panel 14 and its supports, sidewall 17 and Y-shaped support 21. Several suitable types as insulating battings are available on the market, One of the suitable types for such purposes is marketed in under the trade name of FIBER- FRAX, and is made from aluminum oxide, this particular insulating material being suitable for temperatures up to approximately 3000 F. Another batting is marketed under the trade name KOAWOOL and is made from pure kaolin clay. This batting is suitable for temperatures up to 2300 F. One type of batting which as yet does not have a trade name is made from zirconium oxide and is suitable for temperatures up to 4200 F. These ceramic fibers and other battings are available for a wide range of temperatures.

It can be seen from FIG. 1, the lateral restraining force generating means 26 on each of the corner blocks 18 of the walls 10-13 retains and controls the expansion of the walls while firmly supporting the walls in the desired position.

When a side door is required, an entire Wall, such as wall 12 (FIG. l), may be attached to a suitable mechanical means (not shown), as are well known in the art, to swing it out, up or sideways without difliculty. r[The corner walls 19 are fixed and constructed to maintain the structure. It is obvious that proper mechanical arrangements would be simple and easy to apply to the wall, particularly in View of the fact that the door would be exceptionally light in weight as compared to the usual type and could easily close to retain adequate sealing. Flexible asbestos hose connections or rotatable connections could supply the proper fuel-air mixture to the gas chambers Without interference from periodic door openings. If a top loading or bottom loading position is desired, then only the iloor or roof of the furnace 8 need be removed. The bottom portion of all of the individual heating elements comprising the four walls also preferably have high-temperature ceramic batting material between the insulating furnace iioor and the abutting surfaces of walls 10-13 Like provisions are preferably provided for the upper portion in respect to the insulating roof. The iioor and the roof materials do not require tension holding devices for proper sealing in most cases since the normal weight factors involved would be adequate; however, they Should be firmly secured in any desired manner.

By tthe described batting insulation procedure, the expansion and contraction forces involved in any plane will not create hazardous conditions. Furthermore, the gas-sealing is suiiicient to maintain any required atmospheric conditions in the heating chamber of the furnace.

In the expansion of the individual heating panels 14, the insulating materials 1711 of the sidewalls 17 and batting layer 24 as well as the spring loading of the spring 27 and holding stud 26 absorb the expansion and tension caused by different rates of expansion of the various elements of furnace 8 while maintaining a proper seal `between the gas chamber or duct 15 and the burning surface and interior of the furnace.

Although there have been depicted in FIGS. 1 through 4, a furnace in which four Walls are entirely comprised of radiant heating elements 14, it is obvious that one or two walls or part of a single wall might be constructed of the radiant heating panels 14 without departing from the spirit of the invention.

It is now obvious that a new and improved device of a unique type of gas chamber luminous wall construction which effectively eliminates many of the prior art disadvantages has been provided. In allowing for gradual labsorption of the tension and force created by the thermal expansion at varying rates of the various elements and supporting members involved, while at the same time maintaining the seal between the explosive gaseous mixture and the burning panels the described device allows both heating and cooling of the apparatus to be achieved quickly. The described construction simply and inexpensively allows for a wide degree -of contraction or expansion without firing element cracks or other hazardous conditions.

It will be apparent that many modifications and Variations may be effected without departing from the scope and the novel concepts of the present invention.

VI claim as my invention:

1. A gaseous fuel burning device having a plurality of walls defining -a chamber comprising:

a plurality ofY gaseously porous ceramic firing panels having firing surfaces and gaseous fuel input surfaces;

means for mounting said plurality of ceramic firing panels in at least one of said walls with said firing surfaces facing generally into said chamber, said firing surfaces being arranged in juxtaposed pairs at an angle to one another so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of firing surfaces, said means for mounting said plurality of ceramic firing panels Comprising resilient means operating between said panels and said walls; and

means including the gaseous input surfaces of said firing panels for defining -a plenum whereby a fiammable gaseous fuel is supplied to said firing surfaces of said firing panels.

2. A gaseous fuel burning device having a plurality of wall elements defining a chamber comprising:

a plurality of gas permeable ceramic firing panels having generally rectangular firing surfaces and gaseous fuel input surfaces;

means for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber, said firing surfaces being arranged in ljuxtaposed pairs at an angle to one another so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of firing surfaces, said means for mounting said plurality of ceramic firing panels comprising thermal expansion absorbing and preventing means including high temperature ceramic batting between said firing panels and panel supporting elements of said mounting means, said mounting means further comprising resilient means operating between said panels and said wall elements; and

means including the gaseous input surfaces of said firing panels for defining a plenum whereby a fiammable gaseous fuel is supplied under pressure to said firing surfaces of said firing panels.

3. A gaseous fuel burning device having a plurality of wall elements defining a chamber comprising:

a plurality Yof gas permeable ceramic firing 4panels having generally rectangular firing surfaces and gaseous fuel input surfaces;

means including Va plurality of sidewalls for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber and arranged in juxtaposed pairs at an angle to one another so that each of said pair of ring surfaces partially faces the other to allow interchange of radiant heat between said pair of firing surfaces,

said firing panels'being afiixed at their outer endsv to said side walls, said mounting means comprising thermal expansion absorbing and preventing means including high temperature ceramic batting between said firing panels and said sidewalls and spring means affixed to said wall element to absorb and restrain thermal expansion of said wall element; and

means including the gaseous input surfaces of said firing panels and said sidewalls for defining a plenum whereby a ammable gaseous fuel is supplied under pressure to said firing surfaces of said firing panels.

4. A gaseous fuel burning device having a plurality of wall elements defining a chamber comprising:

a plurality of gas permeable ceramic firing panels having generally rectangular firing surfaces and gaseous fuel input surfaces;

means including a plurality of sidewalls for mounting said plurality of ceramic firing panels in at least one Iof said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber `and arranged in juxtaposed pairs at an angle to one another so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of surfaces, said firing panels being afiixed at their outer ends to said sidewalls by a plurality of resilient urging means for urging said firing panels toward said sidewalls and for absorbing thermal expansion of said panels and side sidewall, said-means for mounting said plurality of ceramic firing panels also comprising means including high temperature ceramic batting between said ring panels and said sidewalls which batting is compressed by said urging means and forms a seal to prevent gaseous leakage between said firing panels and said sidewalls; and

means including the gaseous input surfaces of said firing panels and said sidewalls for defining a plenum whereby a fiammable gaseous fuel is supplied under pressure to said firing surfaces of said fir-ing panels.

5. A gaseous fuel burning device having a plurality of j Wall elements defining a chamber comprising:

a plurality of gas permeable ceramic firing panels having generally rectangular firing surfaces and Vgaseous fuel input surfaces;

means including a plurality of sidewalls for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber and arranged in juxtaposed pairs at an angle to one another so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of surfaces, said firing panels being afiixed at their outer ends to said sidewalls, said means for mounting said plurality of ceramic firing panels comprising thermal expansion absorbing and preventing means including urging means for urging said panels againstsaid sidewalls and high temperature batting between said ring panels and said sidewalls which is compressed by said urging means to form a seal and prevent gaseous leakage between said firing panels and said sidewalls;

means for absorbing thermal expansion tension positioned at the end of said wall element having said panels mounted therein; and

means including the gaseous input surfaces of said firing panels and said sidewalls for defining a plenum whereby a fiammable gaseous fuel is supplied under pressure to said firing surfaces of said ring panels.

6. A gaseous fuel buring device having a plurality of wall elements defining a chamber comprising:

a plurality of gas permeable catalytic ceramic firing panels having generally rectangular ring surfaces and gaseous fuel input surfaces;

means including a plurality of vertical sidewalls for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally Vertical position with said firing surfaces facing into said chamber and arranged in juxtaposed pairs at an angle to one another so that each of said pair of ring surfaces partially faces the other to allow interchange of radiant heat between said pair, said firing panels being affixed at their outer ends to said sidewalls by a plurality of resilient urging means including a plurality of studs passing from said firing panels into said sidewall and spring means aliixed'to said studs within said sidewall for urging said firing panels toward said sidewalls, said means formounting said plurality of ceramic firing panels also including high temperature ceramic batting between said firing panels and said sidewalls which batting is compressed by saidY urging means and forms a seal to prevent gaseous leakage between said firing panels and side sidewalls;

and

means including the gaseous input surfaces of said firing panels and said sidewalls for `defining a plenum whereby a flammable gaseous fuel is supplied under pressure to said ring surfaces of said firing panels.

7. A gaseous fuel burning device having a plurality of wall elements defining a chamber comprising:

a plurality of gas permeable catalytic ceramic firing panels having generally racetangular firing surfaces and gaseous fuel input surfaces;

means including a plurality of vertical side walls for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally vertical position with said firing surfaces facing into said chamber and arranged in juxtaposed pairs at an angle to one another so that each of said pair of ring surfaces partially faces the other to allow interchange of radiant heat between said pair, said firing panels being lafixed at their outer ends to said side walls by a plurality of resilient urging means including a plurality of studs passing from said firing panels into said sidewall and spring means affixed to said studs for urging said firing panels toward said sidewall, said means for mounting said plurality of ceramic firing panels also including high temperature ceramic batting between said firing panels and said sidewalls which batting Iis compressed by said urging means and forms a seal to prevent gaseous leakage between said firing panels and said side walls;

compression spring means mounted at a vertical end of said one wall element to absorb and retain the thermal expansion of said wall element in the vertical direction; and

means including the gaseous input surfaces of said sidewalls for defining a plenum whereby a flammable gaseous fuel is supplied under pressure to said ring surfaces of said firing panels.

8. A gaseous fuel burning device providing heat to a combustion chamber primarily by radiant energy, including at least one generally vertical wall defining said chamber comprising:

a plurality of gas permeable catalytic ceramic firing panels having generally rectangular gaseous fuel input surfaces and firing surfaces, each ring surface juxtaposed to another firing surface along a longer side of said rectangular surface, each firing surface being disposed in a vertical plane at an angle to the vertical plane of said one wall, each of said firing surfaces facing generally into said chamber and canted toward a juxtaposed surface to radiate heat thereof;

means for mounting said panels including a plurality of Vertical insulated sidewall elements supporting said panels along the longer rectangular side of said surface, a backing element cooperating with said last named means to define a plurality of vertical plenum chambers behind said panels away from said chamber;

high temperature ceramic batting between said firing panels and said insulated sidewalls;

a plurality of studs attached to said tiring panels and passing through said batting into said sidewalls, spring means attached to said studs within said sidewalls for resiliently urging said panels toward said sidewalls; and

means for absorbing lateral expansion of said one wall including compression spring means, and a movable block positioned at one end of said one wall and abutting said spring means.

9. A gaseous fuel burning device comprising: a plurality of wall elements defining a chamber;

a plurality of gas permeable ceramic ring panels having generally rectangular firing surfaces and gaseous fuel input surfaces;

means including a plurality of sidewalls for mounting said plurality of ceramic firing panels in at least one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber, said tiring surfaces being arranged in juxtaposed pairs at an angle to one another so that each Of said pairs of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of tiring surfaces by a plurality of resilient urging means spaced along the ends of said firing panels;

said urging means including a stud passing through said iirinig panels into said sidewall and comprising means for resiliently urging said stud into said sidewall, said means for mounting said plurality of ceramic firing panels comprising thermal expansion absorbing means including high temperature between said firing panels and said sidewalls which is compressed by said urging means and forms a gaseous seal to prevent gaseous leakage between said firing panels and said sidewalls; and

means including the gaseous input surfaces of said firing panels and said sidewalls for defining a plenum whereby a flammable gaseous fuel is supplied to said firing surfaces of said firing panels.

10. A gaseous fuel burning device comprising: a plurality of wall elements defining a chamber;

a plurality of gas permeable ceramic ring panels having generally rectangular firing surfaces and gaseous fuel input surfaces;

means including a plurality of sidewalls for mounting said plurality of ceramic firing panels in one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber, said firing surfaces being arranged in juxtaposed pairs at an angle to one another so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of firing surfaces, said firing panels being affixed at their outer ends to said sidewalls, said means for mounting said plurality of ceramic firing panels comprising thermal expansion absorbing means to absorb the thermal expansion of said tiring panels;

means including a compression spring mounted at one end of said wall element to absorb and retain the thermal expansion of said firing panels and said wall element during the thermal contraction of said wall element and firing panels; and

means including the gaseous input surfaces of said firing panels and said sidewalls for defining a plenum whereby a ammable gaseous fuel is supplied under pressure to said firing surfaces of said tiring panels.

11. A gaseous fuel burning device comprising a plurality of wall elements defining a chamber;

a plurality of gas permeable ceramic firing panels having generally rectangular ring surfaces and gaseous fuel input surfaces;

means including a plurality of sidewalls for mounting said plurality of ceramic ring panels in one of said wall elements in a generally vertical position with said firing surfaces facing generally into said chamber, said firing surfaces being arranged in pairs so that one firing surface is in juxtaposition to another firing surface but at an angle to said juxtapositioned firing surface so that each of said pair of firing surfaces partially faces the other to allow interchange of radiant heat between said pair of firing surfaces during operation of said device, said firing panels being aixed at their outer ends to said sidewalls, said means for mounting said plurality of ceramic firing panels comprising thermal expansion absorbing means including high temperature batting between said ring panels and said sidewalls which is compressed by said urging means and forms a gaseous l l seal to prevent gaseous leakage between said ring panels and said sidewalls,

a plurality of backwall elements vertically mounted between said sidewalls;

an end block element, generally vertically positioned at the end of said wall with one vertical side against the end of said wall element;

a xed corner wall abutting against another side of said block element; and

compression spring means to exert force against said end block element on a vertical surface of said end block element and to absorb and contain the thermal expansion of said wall element.

12. A gaseous fuel burning device of the furnace type comprising four generally vertical walls joining one another in four corners dening a furnace chamber, each of said Walls comprising:

a plurality of rectangular gas permeable ceramic firing panels having rectangular firing surfaces facing into said furnace cham-ber and an oppositely situated gaseous fuel input surface, said panels being vertically oriented in said Walls in juxtaposed pairs, each panel of said pairs being oriented and related to the other at an angle t0 form a V configuration;

a backwall spaced from said pairs of panels away from said furnace chamber;

a generally Y-shaped support mounted on said backwall and extending outwardly therefrom to mate the junction of said panel pair in the arm'elements of said Y-shaped support;

`a thin layer of high temperature ceramic batting between said panel pair junction and said arms of said Y-shaped support;

a pair of vertical sidewalls each consisting of two metal sheets with thermal insulation therebetween, said thermal insulation extending beyond said metal l2 sheets at one end of said sidewall, and aixed to each end of said backwall and extending to an end of said V-shaped panel pair, said sidewall being shaped to receive said panel ends with said thermal insulation extending beyond said metal sheets between the end of said panel and a juxtaposed panel; a thin layer of high temperature ceramic batting between said panel end and said sidewall; means for fastening said paneds to said sidewall comprising a stud extending into said metal sheet of said sidewall, and a compression spring in said sidewall afixed to the end of said stud for urging said stud and said panel into said wall and for compressing said batting between said side wall and said panel; four corner expansion restraining and absorbing means comprising a xed vertical corner wall positioned at an angle to said wall forming said corner, a tri-vertical sided block fo reach of said corner forming walls abutting on one vertical side against said corner wall and abutting over another vertical side against the end of said corner forming wall; and spring tensioning means having a fixed end away from the third vertical side of said tri-vertical sided block and a free end against said third vertical side to restrain and absorb the thermal expansion of said walls.

References Cited UNITED STATES PATENTS 1,731,053 10/1929 Lowe 158-99 2,828,813 4/1958 Holden 158--7 FOREIGN PATENTS 1,129,123 9/1956 France.

FREDERICK L. MATTESON, JR., Primary Examiner. E. G. FAVORS, Assistant Examiner. 

1. A GASEOUS FUEL BURNING DEVICE HAVING A PLURALITY OF WALLS DEFINING A CHAMBER COMPRISING: A PLURALITY OF GASEOUSLY POROUS CERMAIC FIRING PANELS HAVING FIRING SURFACES AND GASEOUS FUEL INPUT SURFACES; MEANS FOR MOUNTING SAID PLURALITY OF CERAMIC FIRING PANELS IN AT LEAST ONE OF SAID WALLS WITH SAID FIRING SURFACES FACING GENERALLY INTO SAID CHAMBER, SAID FIRING SURFACES BEING ARRANGED IN JUXTAPOSED PAIRS AT AN ANGLE TO ONE ANOTHER SO THAT EACH OF SAID PAIR OF FIRING SURFACES PARTIALLY FACES THE OTHER TO ALLOW INTERCHANGE OF RADIANT HEAT BETWEEN SAID PAIR OF FIRING SURFACES, SAID MEANS FOR MOUNTING SAID PLURALITY OF CERAMIC FIRING PANELS COMPRISING RESILIENT MEANS OPERATING BETWEEN SAID PANELS AND SAID WALLS; AND MEANS INCLUDING THE GASEOUS INPUT SURFACES OF SAID FIRING PANELS FOR DEFINING A PLENUM WHEREBY A FLAMMABLE GASEOUS FUEL IS SUPPLIED TO SAID FIRING SURFACES OF SAID FIRING PANELS. 